Method for separating stator windings of an electric motor during manufacture

ABSTRACT

A technique for separating the stator leads of an electric motor during the manufacturing process. The technique comprises a system having a lead gathering assembly, a lead separator, and a drive mechanism. The lead gathering assembly is adapted to gather together a plurality of stator windings extending from a stator. The lead separator having a plurality of teeth adapted to separate a stator winding from the plurality of stator windings gathered together by the lead gathering assembly. The drive mechanism is adapted to drive the lead separator into the plurality of stator windings. The lead separator has teeth to separate each of the stator windings gathered together by the lead gathering assembly.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of Application No. 09/967,364,filed on Sep. 28, 2001.

BACKGROUND OF THE INVENTION

[0002] The present invention relates generally to the field of electricmotors and methods and apparatus for manufacturing electric motors. Moreparticularly, the invention relates to a novel technique for separatingstator winding conductors of a randomly wound stator.

[0003] Electric motors of various types are omnipresent in industrial,commercial and consumer settings. In industry, such motors are employedto power all types of rotating machinery, such as pumps, conveyors,compressors, fans and so forth, to mention only a few. Conventionalalternating current electric motors may be constructed for single ormultiple phase operation, and are typically specifically designed tooperate at predetermined synchronous speeds, such as 3600 rpm, 1800 rpm,1200 rpm and so on. Such motors generally include a stator, comprising amultiplicity of coils, surrounding a rotor which is supported bybearings for rotation in the motor frame. In the case of AC motors,alternating current power applied to the motor causes the rotor torotate within the stator at a speed which is a function of the frequencyof alternating current input power and of the motor design (i.e., thenumber of poles defined by the motor windings and rotor resistance). InDC motors power is similarly applied, and the speed of the motor may becontrolled in a variety of manners. In both cases, however, a rotorshaft extends through the motor housing and is connected to elements ofthe machinery driven by the electric motor.

[0004] In conventional electric motors, conductors, known as statorwindings; are routed through parallel slots formed around the innerperiphery of a metallic core. The stator windings are electricallyconnected in groups around the stator core to form electro-magneticcoils. The coils establish the desired electro-magnetic fields used toinduce rotation of the rotor. The number and locations of the windingsin the stator core generally depends upon the design of the motor (e.g.,the number of poles, the number of stator slots, the number of windinggroups, and so forth). Each winding coil includes a number of turns ofwire that loop around end or head regions of the stator between theslots in which the winding coil is installed. Multiple conductors arewound in each slot in a randomly wound stator. Following installation inthe slots, the coils in each group are generally pressed into a bundleat either end of the stator. The stator windings are connected toelectrical wiring that is routed from the stator to a wiring or conduitbox located on the outside of the motor through corresponding holes inthe motor frame and the conduit box.

[0005] While conventional motor manufacturing equipment and methods havebeen generally satisfactory in many applications, they are not withoutdrawbacks. For example, each stator winding must be separated from theother stator windings so that the stator windings may be electricallyconnected in the proper configuration. Wiring the stator windings in thewrong configuration will decrease the performance of the motor, if themotor is able to operate at all. However, separating the stator windingsby hand is time-consuming and increases the cost of manufacturing themotor.

[0006] There is a need, therefore, for an improved technique forseparating the stator windings of an electric motor after they have beenwound on the stator. There is a particular need for a technique thatprovides the equipment and/or a method for automatically separating thestator windings of an electric motor during the electric motormanufacturing process.

SUMMARY OF THE INVENTION

[0007] The invention provides a novel approach to manufacturing anelectric motor designed to respond to these needs. The technique can beemployed in various motor configurations, including AC and DC motors,and motors configured with 2, 4, 6 or more poles, for single or multiplephase operation, and from fractional horsepowers to very large powerratings.

[0008] In accordance with the first aspect of the technique, a system isprovided for manufacturing an electric motor. The system comprises alead gathering assembly, a lead separator, and a drive mechanism. Thelead gathering assembly is adapted to gather together a plurality ofstator windings extending from a stator. The lead separator has aplurality of teeth adapted to separate a stator winding from theplurality of stator windings gathered together by the lead gatheringassembly. The drive mechanism is adapted to drive the lead separatorinto the plurality of stator windings.

[0009] In accordance with another aspect of the technique, a method ofmanufacturing an electric motor is provided. The method comprisesdisposing a stator having a plurality of stator leads into a leadseparating assembly. The method also comprises gathering the pluralityof stator leads together. The method also comprises driving a leadseparator into engagement with the plurality of stator leads gatheredtogether to separate each of the plurality of stator leads gatheredtogether.

[0010] In accordance with another aspect of the technique, a leadseparator for a lead separating system is provided. The lead separatorcomprises a plurality of teeth disposed around the lead separator. Theteeth are adapted to separate individual stator leads from among aplurality of stator leads and direct the stator leads towards a desiredlocation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing and other advantages and features of the inventionwill become apparent upon reading the following detailed description andupon reference to the drawings in which:

[0012]FIG. 1 is a perspective view of an electric motor illustrating thevarious functional components of the motor including a rotor and astator, in accordance with certain aspects of the invention;

[0013]FIG. 2 is an elevational view of a stator having a plurality ofstator winding conductors and a portion of a device for separating thestator winding conductors, illustrating the insertion of aclamp/expander and lead separator into the stator;

[0014]FIG. 3 is an elevational view of a stator having a plurality ofstator winding conductors and a portion of a device for separating thestator winding conductors, illustrating the expansion of theclamp/expander to secure the clamp/expander and lead separator to thestator;

[0015]FIG. 4 is an elevational view of a stator having a plurality ofstator winding conductors and the device for separating the statorwinding conductors, illustrating the operation of the device incollecting the stator winding conductors into a bundle;

[0016]FIG. 5 is a top view of a portion of the device for separating thestator winding conductors, illustrating the operation of the portion ofthe device in securing the stator winding conductors into a bundle;

[0017]FIG. 6 is an elevational view of a stator having a plurality ofstator winding conductors and a portion of the device for separating thestator winding conductors, illustrating the operation of the device inapplying tension to the stator winding conductors in the bundle;

[0018]FIG. 7 is an elevational view of a stator having a plurality ofstator winding conductors and a portion of the device for separating thestator winding conductors; illustrating the operation of the leadseparator in separating individual stator winding conductors from thebundle of stator winding conductors;

[0019]FIG. 8 is a top view of the lead separator; and

[0020]FIG. 9 is an elevational view of a stator having a plurality ofindividually separated stator winding conductors, illustrating theidentification of each of the stator winding conductors.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0021] Turning now to the drawings, and referring first to FIG. 1, anelectric motor is shown and designated generally by the referencenumeral 20. In the embodiment illustrated in FIG. 1, motor 20 is aninduction motor housed in a conventional NEMA enclosure. Accordingly,motor 20 includes a frame 22 open at front and rear ends and capped by afront end cap 24 and a rear end cap 26. The frame 22, front end cap 24,and rear end cap 26 form a protective shell, or housing, for a statorassembly 28 and a rotor assembly 30. Stator windings are electricallyinterconnected to form groups, and the groups are, in turn,interconnected. The windings are further coupled to terminal leads 32.The terminal leads 32 are used to electrically connect the statorwindings to an external power cable (not shown) coupled to a source ofelectrical power. Energizing the stator windings produces a magneticfield that induces rotation of the rotor assembly 30. The electricalconnection between the terminal leads and the power cable is housedwithin a conduit box 34.

[0022] In the embodiment illustrated, rotor assembly 30 comprises a castrotor 36 supported on a rotary shaft 38. As will be appreciated by thoseskilled in the art, shaft 38 is configured for coupling to a drivenmachine element (not shown), for transmitting torque to the machineelement. Rotor 36 and shaft 38 are supported for rotation within frame22 by a front bearing set 40 and a rear bearing set 42 carried by frontend cap 24 and rear end cap 26, respectively. In the illustratedembodiment of electric motor 20, a cooling fan 44 is supported forrotation on shaft 38 to promote convective heat transfer through theframe 22. The frame 22 generally includes features permitting it to bemounted in a desired application, such as integral mounting feet 46. Aswill be appreciated by those skilled in the art, however, a wide varietyof rotor configurations may be envisaged in motors that may employ themanufacturing techniques outlined herein, including wound rotors of thetype shown, permanent magnet rotors, and so forth.

[0023] Electric motors are typically manufactured using an assembly lineprocess. In one part of the process of manufacturing a randomly woundmotor, multiple stator windings are placed in slots along the length ofthe stator. Referring generally to FIGS. 2-9, a process of separatingthe multiple stator windings in each slot for further manufacturingsteps, such as stator winding identification, labeling, and routing, isillustrated.

[0024] Referring generally to FIG. 2, a stator 48 secured to a pallet 50is illustrated. The pallet 50 is used to handle the stator 48 through avariety of manufacturing steps. The stator 48 includes a core 52 havingslots 54 around the inner periphery of the core 52. In the illustratedembodiment, the stator windings 56 are wound on the core 52 with aplurality of stator windings 56 located in each slot 54 within the core52 of the stator 48. In this view, the stator windings 56 are routedupward for connection to the terminal leads 32 (not shown). In theillustrated embodiment, the stator windings 56 extended freely from thestator 48 and are not physically separated from each other. A leadseparator 58 is used to separate each stator winding 56 from the otherstator windings. A clamp/expander 60 is used to maintain the leadseparator engaged 58 against the stator windings 56.

[0025] The lead separator 58 and clamp/expander 60 are raised into thestator core 52 by one or more motorized systems 62, as represented bythe arrow 64. The motorized systems 62 may include electric motors,hydraulic motors, servos, etc. The motorized systems 62 also areoperable to position the lead separator 58 relative to theclamp/expander 60. The clamp/expander 60 may be de-coupled from themotorized systems 62 to enable the clamp/expander 60 to be transportedwith the stator 28 to another location for further manufacturing.

[0026] Referring generally to FIG. 3, the motorized systems 62 also areoperable to secure the clamp/expander 60 to the core 52 of the stator48. In the illustrated embodiment, arms 66 of the clamp/expander 60 aredriven outward against an interior surface 68 of the stator 48, asrepresented by the arrow 70. The clamp/expander 60 has a lockingmechanism (not shown) that maintains the arms 64 of the clamp/expander60 locked against the interior surface 68 of the stator 48, clamping theclamp/expander 60 to the core 52. The locking mechanism is operable tomaintain the clamp/expander 60 engaged against the stator 48 so that theclamp/expander 60 and the lead separator 58 may be disengaged from themotorized systems 62, yet remain secured to the stator 48.

[0027] Referring generally to FIG. 4, a spiral auger 72 and a clamp 74are used to secure the stator windings 56 into a bundle. The spiralauger 72 is placed over the loose stator windings 56. The spiral auger72 is then rotated, as represented by the arrow 76. The spiral auger 72grabs the stator windings 56 as the spiral auger 72 is rotated, windingthe stator windings 56 into a bundle. As best illustrated in FIG. 5, theclamp 74 is then closed onto the bundle of stator windings 56, asrepresented by the arrows 78. The spiral auger 72 may then be removedwithout the bundle of stator windings 56 unraveling. The spiral auger 72is removed by rotating the spiral auger 72 in the opposite direction ofrotation. Referring generally to FIG. 6, the clamp 74 is then raised, inthis view, to draw the stator windings 56 taut, as represented by thearrows 80. Applying tension to the stator windings 56 removes the slackfrom the stator windings 56 so that the stator windings 56 may be moreeasily separated.

[0028] Referring generally to FIG. 7, one or more motor systems 64 arethen used to drive the lead separator 58 upward through the stator 48,as represented by the arrows 82. The lead separator 52 has a shaft 84that enables the lead separator 58 to be positioned relative to theclamp/expander 60. As best illustrated in FIG. 8, the lead separator 58has a plurality of teeth 86 extending around the circumference of thelead separator 58. In the illustrated embodiment, each tooth 86 has apoint 88 formed by two angled surfaces 90. The points 88 of the tooth 86are used to separate the stator windings 56 as the lead separator 58 israised into contact with the cone of stator windings 56. Additionally,each tooth has a second pair of surfaces 92. As the lead separator 58 israised higher, the angled surface 90 and the second pair of surfaces 92direct the stator windings toward an inner portion 94 as represented bythe arrow 96. The inner portion 94 of the lead separator 58 has a layerof flexible material 98, such as rubber. The flexible material 98 has aslot 100. Each of the stator windings 56 is directed into one of theslots 100. The slots 100 capture the stator windings 56, restraining themovement of the stator windings 56. The stator windings 56 may now beelectrically connected in the desired configuration.

[0029] Additionally, the lead separator 58 and clamp/expander 60 areadapted so that the stator 48 and pallet 50 may be removed, along withthe lead separator 58 and clamp/expander 60, and moved to anotherassembly station for further assembly. The lead separator 58 andclamp/expander 60 also are operable to maintain the lead separator 58extended when the lead separator 58 and clamp/expander 60 are disengagedfrom the motorized systems 62. A reference mark 102 is used to enable aspecific stator winding to be marked as a reference point. In theillustrated embodiment, a dot is placed on one of the teeth to serve asa reference mark 102. However, each winding also may be individuallymarked, such as by placing numbers around the lead separator to markeach stator winding or slot.

[0030] Referring generally to FIG. 9, each stator winding may now beidentified by its position around the circumference of the leadseparator 58. The core 52 may have a mark to identify a specific statorwinding as a reference point. For example, placing an identifier 104 ona stator winding, as illustrated in FIG. 9, may be performed to identifya specific stator winding 56. Additionally, the labeling, or otherprocessing, may be performed at a different station by moving the pallet50 and, thus, the stator 48, lead separator 58, and clamp/expander 60 toa different manufacturing station. The movement of the pallet 50 may beperformed manually or through the use of a motorized system.

[0031] The above technique enables the stator windings of an electricmotor to be separated by machine, rather than manually. Additionally,the technique enables the stator windings to be maintained separatedduring portions of the electric motor manufacturing process, includingduring movement of the stator. The above technique also enables specificstator windings to be located.

[0032] While the invention may be susceptible to various modificationsand alternative forms, specific embodiments have been shown in thedrawings and have been described in detail herein by way of exampleonly. However, it should be understood that the invention is notintended to be limited to the particular forms disclosed. Rather, theinvention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by thefollowing appended claims.

What is claimed is:
 1. A method of manufacturing an electric motor,comprising: disposing a stator having a plurality of stator leads into alead separating assembly; gathering the plurality of stator leadstogether into a bundle; and driving a lead separator through the statorinto engagement with the plurality of stator leads gathered together toseparate each of the plurality of stator leads gathered together.
 2. Themethod as recited in claim 1, wherein disposing comprises securing thestator to a pallet adapted to position the stator within a stator leadseparating device.
 3. The method as recited in claim 1, wherein theplurality of stator leads extend freely from the stator.
 4. The methodas recited in claim 3, wherein gathering comprises placing the pluralityof stator windings extending freely from the stator into a leadcollector and rotating the lead collector to wind the stator leadstogether.
 5. The method as recited in claim 1, wherein gatheringcomprises securing a clamp to the plurality of stator leads gatheredtogether.
 6. The method as recited in claim 5, wherein gatheringcomprises utilizing the clamp to apply tension to the plurality ofstator leads gathered together.
 7. The method as recited in claim 1,wherein driving comprises utilizing a motorized apparatus to drive thelead separator through the stator.
 8. The method as recited in claim 1,further comprising providing a lead separator with a plurality ofoutwardly extending teeth disposed circumferentially around the leadseparator, wherein each tooth is adapted to penetrate the plurality ofstator leads gathered together and to separate each the plurality ofstator leads gathered together.
 9. The method as recited in claim 8,wherein providing comprises providing a lead separator adapted toindividually restrain each of the plurality of stator leads gatheredtogether.
 10. The method as recited in claim 9, wherein the plurality ofteeth cooperate to direct each of the plurality of stator leads towardsthe flexible material.
 11. The method as recited in claim 8, whereinproviding comprises identifying the number of stator leads in theplurality of stator leads and providing a lead separator with the samenumber of teeth as the number of stator leads.
 12. The method as recitedin claim 1, further comprising securing the lead separator to a statorclamp secured to the stator to maintain each stator lead separated. 13.The method as recited in claim 12, further comprising removing thestator, stator clamp, and lead separator from the lead separating devicefor movement to another electric motor manufacturing device.
 14. Amethod of separating stator winding leads of an electric motor duringmanufacture, comprising: operating a rotating lead collector to gather aplurality of stator winding leads extending from a stator into a bundle;and driving a lead separator through the stator into the bundle ofstator winding leads to separate each stator winding lead tooth of themulti-toothed lead separator between a pair of stator winding leads inthe bundle of stator winding leads.
 15. The method as recited in claim14, comprising driving a clamp against the bundle of stator windingleads to maintain the bundle of stator windings bundled.
 16. The methodas recited in claim 14, wherein driving a multi-toothed lead separatorinto the bundle of stator winding leads comprises driving the leadseparator through the stator core.
 17. The method as recited in claim14, comprising affixing the stator core to a pallet.
 18. The method asrecited in claim 14, comprising securing a lead identifier to each ofthe stator winding leads.
 19. A method of manufacturing an electricmotor, comprising: operating a rotating lead collector to collect aplurality of stator winding leads extending from a stator into a bundle;driving a lead separator into the bundle of stator leads to individuallyseparate each of the plurality of stator leads gathered together; andsecuring the lead separator to the stator to maintain the plurality ofstator leads separated.
 20. The method as recited in claim 19,comprising securing the stator to a pallet.
 21. The method as recited inclaim 20, comprising disposing the stator and pallet into a leadseparating assembly to enable the lead separator to be driven into thestator.
 22. The method as recited in claim 21, comprising removing thestator, pallet, and lead separator from the lead separating mechanismafter securing the lead separator to the stator to maintain theplurality of stator leads separated.